Comparisons Between Selected Three-Dimensional Yield Criteria Applied to Rock

This article focuses on two broad categories of yield criteria: those based on the Hoek–Brown yield criterion and a range of other widely used criteria. The first group of criteria source their input data from uniaxial compressive strength, coupled with mineralogical and structural properties of the rock. The second group of selected criteria, here referred to as ‘frictional criteria’, source their input data from one or more of the parameters uniaxial compressive strength, cohesion and friction. Although some authors have attempted to compare the predictions of the wide range of published criteria, the results have not been entirely satisfactory due to disparities in the input data and the difficulties in extrapolating a two-dimensional criterion into three-dimensions. This article presents a strategy for achieving a consistent basis for comparing three-dimensional yield criteria for rock. This strategy is based on using the two-dimensional Hoek–Brown criterion as a single ‘front end’ for calculating the input parameters for the selected frictional criteria. In essence, four amended yield criteria have been defined: the Hoek–Brown–Drucker–Prager (which is a close approximation to the comprehensive Priest criterion); the Hoek–Brown-Coulomb; the Hoek–Brown-modified Wiebols and Cook; and the Hoek–Brown-modified Lade. The predictions of these criteria, and also the comprehensive Zhang-Zhu criterion, can be approximated over a limited range of intermediate principal stress by selecting a value for the weighting factor w between 0.2 and 0.5 in the simplified Priest criterion to achieve the appropriate sensitivity to the intermediate effective principal stress.